There are numerous accessory components and systems utilized with vehicle engines today. Many of these accessories are driven or operated by a serpentine belt driven directly or indirectly by the crankshaft of the engine. A pulley member is typically included on, or in connection with, the accessory and used in cooperation with the belt to drive or operate the accessory. Accessories of this type include air conditioning compressors, cooling fans, water pumps, alternators and the like.
Pulleys driven by engine belt members are typically included in fan drive assemblies and water pump drives, which may also include friction clutch assemblies or viscous drive assemblies. These clutch and drive assemblies typically have internal mechanisms or components which regulate or control the operation of the accessories relative to the input speed of the engine from the belt and pulley mechanism.
Some of these accessory drive assemblies have internal electromagnetic clutch mechanisms or systems which control the engagement of the fan drives and thus control the speed of the fan. Control systems based, for example, on sensor input, can be utilized to control the operation of the electromagnetic clutch or drive system.
In the electromagnetic systems of such accessory drives, the pulley member, or portions thereof, can be positioned in the electromagnetic flux circuitry as part of a clutch activation or deactivation system. It thus is important to position and structure the pulley and pulley assembly in an appropriate manner. Also, since the pulley members can be exposed to outside environment factors in the engine compartment of the vehicles, it is important to protect and seal the internal components of the accessory drives from a leakage or entry of debris, water, oils and other environmental factors through the pulleys.
It is an object of the present invention to provide an improved pulley operated accessory drive mechanism which is protected from ingress of harmful environment matters. It is also an object to provide an improved pulley member and mechanism for use in water pump and fan drive assemblies, particularly those which utilize electromagnetic clutch mechanisms.